IRC Rating Businesses and Services

IRC Rating Dufour
Dufour 34 Performance Cruiser - The IRC Rating LL/P anomaly.
Following on from my study of Dufour Performance Cruisers vs. various regression rating systems (including IRC), with the sometimes huge variances between Dufour 34 Performance Cruiser and similar yachts such at X-34, and also compared to the the data IMS type VMG models.

IRC Rating LL/P
Performance Cruisers - The IRC Rating LL/P debate.
Following on from my study of Performance Cruisers vs. various rating systems (including IRC), and the sometimes huge variances between similar yachts and on the water performances as well as to IMS type VMG models. Most single number regression formula?s use a combined sail area in model (with various weightings such as main at 100% and foresail at 60% to allow for upwind tacking, and 40% for downwind with spinnaker).